Drilling Fluid affects MWD Magnetic Azimuth and Wellbore Position

Torkildsen, Torgeir; Edvardsen, Inge; Fjogstad, Arild; Saasen, Arild; Amundsen, Per Amund; Omland, Tor

doi:10.2523/87169-ms

Cited by 7 publications

(8 citation statements)

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“…This shielding can cause azimuth errors of 1-2 degrees, and errors even five to ten times larger may occur for certain wellbore directions under unfavourable conditions (Wilson and Brooks 2001;Torkildsen et al 2004;Amundsen, Torkildsen, and Saasen 2006). Thus, magnetic contamination can reduce the borehole position accuracy sufficiently to reduce the probability of hitting the planned target.…”

Section: Introductionmentioning

confidence: 94%

“…The magnetic properties of a drilling fluid is known to depend on such variables as the mineralogical composition of the weight material used (Jiles 1991), contamination of magnetic elements (such as steel) due to mechanical wear of downhole and surface equipment (Shook and Roco 1991;Wilson et al 2006), and the circulation properties of the drilling fluid (Torkildsen et al 2004).…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation of the Magnetic Shielding Effect of Mineral Powders in a Drilling Fluid

Ding

Datta

Saasen

et al. 2010

Particulate Science and Technology

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Magnetic contamination of the drilling fluid shields the Earth's magnetic field measured by the magnetic sensors, and may contribute significantly to errors in directional surveying of a wellbore. A series of laboratory measurements were performed to investigate such magnetic shielding effects. In the measurement, a single axis fluxgate magnetometer was immersed in model drilling fluids prepared by mixing powders of known magnetic properties (magnetite and pure iron) into a solution of xanthan gum in fresh water, whereafter the vertical component of the Earth's field inside the fluid was measured. It was found that the strong shielding effect of dry iron powder essentially vanished when was suspended in the drilling fluid. The magnetic shielding caused by magnetite, however, remained significant also in solution, showing a complex dynamical behaviour. Initially the magnetic field was significantly damped, and this shielding was found to increase further for the next hour or so, reaching a fairly sharp maximum. The shielding then started to decay slowly and irregularly again over the next few days.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Magnetic Shielding Effect of Mineral Powders in a Drilling Fluid

Ding

Datta

Saasen

et al. 2010

Particulate Science and Technology

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“…The conventional measurement-while-drilling (MWD) tool combines three-axis gyroscopes and three-axis magnetometers to provide the attitude (tool face, inclination, and azimuth) of the drill bit. However, the performance of the MWD tools would deteriorate under the strong magnetic interference caused by the following factors: (1) flow of currents in the atmosphere and moving of solar wind [ 5 ]; (2) existing drilling fluid and debris [ 6 , 7 ]; (3) ferromagnetic deposits in the proximity of bottom hole assembly (BHA) [ 8 ]. Non-magnetic drill collars can effectively eliminate the magnetic disturbance; however, the high cost, high weight, and weak fracture drill collars fail to be widely used.…”

Section: Introductionmentioning

confidence: 99%

Particle Filter with Novel Nonlinear Error Model for Miniature Gyroscope-Based Measurement While Drilling Navigation

Yuan

2016

Sensors

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The derivation of a conventional error model for the miniature gyroscope-based measurement while drilling (MGWD) system is based on the assumption that the errors of attitude are small enough so that the direction cosine matrix (DCM) can be approximated or simplified by the errors of small-angle attitude. However, the simplification of the DCM would introduce errors to the navigation solutions of the MGWD system if the initial alignment cannot provide precise attitude, especially for the low-cost microelectromechanical system (MEMS) sensors operated in harsh multilateral horizontal downhole drilling environments. This paper proposes a novel nonlinear error model (NNEM) by the introduction of the error of DCM, and the NNEM can reduce the propagated errors under large-angle attitude error conditions. The zero velocity and zero position are the reference points and the innovations in the states estimation of particle filter (PF) and Kalman filter (KF). The experimental results illustrate that the performance of PF is better than KF and the PF with NNEM can effectively restrain the errors of system states, especially for the azimuth, velocity, and height in the quasi-stationary condition.

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“…This shielding can cause azimuth errors of 1° -2°, and even larger errors may occur for certain wellbore directions under unfavourable conditions (Wilson and Brooks, 2001;Torkildsen et al, 2004;Amundsen et al, 2005;Amundsen et al, 2006;). This shielding can cause azimuth errors of 1° -2°, and even larger errors may occur for certain wellbore directions under unfavourable conditions (Wilson and Brooks, 2001;Torkildsen et al, 2004;Amundsen et al, 2005;Amundsen et al, 2006;).…”

Section: Introductionmentioning

confidence: 99%

“…This study was performed to examine the attenuation of magnetic fields in a wellbore fully or partially filled with magnetically contaminated drilling fluid, and with MWD directional sensors placed inside a tool located at a given position in the wellbore. Torkildsen et al (2004) presented results from two independent methods for measuring magnetic susceptibility of drilling fluids. The phenomenon was demonstrated in several ways, both by laboratory experiments and analyses of magnetic directional survey data.…”

Section: Introductionmentioning

confidence: 99%

The Design of BHA and the Placement of the Magnetometer Sensors Influence How Magnetic Azimuth is Distorted by the Magnetic Properties of Drilling Fluids

et al. 2012

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The magnetic property of the drilling fluid is one of the substantial error sources for the determination of magnetic azimuth for wellbores. Both the weight material, cuttings, clay and other formation material plus metal filings from the tubular wear may distort the magnetometer readings. This effect is obviously linked to the amount and kind of magnetic material in the drilling fluid, and the development of corrective means has therefore highlighted the drilling fluid. The problem has been studied by laboratory experiments and analyses of downhole survey data. However, there are several inconsistencies in the results, and the phenomenon is not fully understood. The geometric properties of the BHA and the magnetic directional tool are focused upon in this study.The influence on directional MWD from drilling fluids has been studied using finite element modeling techniques. The simulations have been performed for several cases with realistic representations of MWD tool geometries and varying location of BHA versus the wellbore. One important result is that for situations with perfect axial symmetry, the magnetometer readings are attenuated proportionally to the square of the magnetic susceptibility. Since the magnetic susceptibility is a small number, this means that the effect on magnetometer readings is generally negligible. However, if the symmetry is broken, the distortion on the magnetometer readings can be increased significantly. This means that segregation of cuttings, metal filings or weight material can strongly influence the strength of the measured magnetic fields.With a collar based tool, that is non-symmetric by nature, the model shows a complex distortion picture. The influence varies with the tool face angle, and shows both attenuation and amplification. The distortion maxima and minima for the two cross-sectional magnetometers do not coincide. These findings underline how hard it will be to find a straight-forward corrective action.The results from the simulations give increased knowledge about the influence from the magnetic properties of the drilling fluid. This is essential for accuracy estimation and multistation analysis of magnetic survey data. Furthermore, the results demonstrate the importance of considering the geometry of the BHA and the tool, and of the sensor placement when performing the mechanical design.

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Drilling Fluid affects MWD Magnetic Azimuth and Wellbore Position

Cited by 7 publications

References 0 publications

Experimental Investigation of the Magnetic Shielding Effect of Mineral Powders in a Drilling Fluid

Experimental Investigation of the Magnetic Shielding Effect of Mineral Powders in a Drilling Fluid

Particle Filter with Novel Nonlinear Error Model for Miniature Gyroscope-Based Measurement While Drilling Navigation

The Design of BHA and the Placement of the Magnetometer Sensors Influence How Magnetic Azimuth is Distorted by the Magnetic Properties of Drilling Fluids

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